Asst. Prof. Ludwig, Alexander
Assistant Professor
Phone: (65) 6908 2212
Email: [email protected]
Personal Lab Webpage: https://blogs.ntu.edu.sg/alabntusg/
My lab investigates how epithelial tissue barriers are formed, organized, and regulated. Epithelial cells are polarised into distinct apical and basolateral domains and form tightly connected tissue sheets that separate diverse body compartments. The asymmetry of epithelial cells is controlled by the Apical Junctional Complex (AJC). The AJC, which is composed of tight junctions and adherens junctions, mediates cell-cell adhesion, provides structural integrity, transmits mechanical signals to the cell cytoskeleton, and is involved in growth control signaling. In addition, the AJC acts as a fence to establish and maintain polarity and controls the flux of molecules across epithelial tissues. Disruptions in epithelial barrier function can lead to developmental abnormalities and contributes to various diseases.
Our research aims to uncover how epithelial cells develop and maintain apico-basal polarity. We particularly focus on the Crumbs complex, a key player in junction formation, polarity establishment, and growth regulation. Additionally, we study the mechanisms behind the assembly and regulation of tight junctions. To do this, we employ biochemical, cell biological, and high-resolution imaging techniques using both 2D and 3D cell culture models.
Research Areas
Cell Biology, Epithelial Cell Polarity, Tight Junctions, Actin Cytoskeleton, Signaling
Research Fellow
PhD Student
Research Fellow
Research Fellow
PhD Student
PhD Student
- Eleanor Martin, Sujasha Ghosh, Yuhong Chen, Barbara Huebner, Kay En Low, Gunnar Dittmar, and Alexander Ludwig. "Bulk exocytosis of large intracellular apical precursor organelles establishes apical domain identity during de novo lumen formation." BioRxiv preprint (2025). https://doi.org/10.1101/2025.03.06.641813
- Hana Maldivita Tambrin, Yun Liu, Zhu Kexin, Teng Xiang, Yusuke Toyama, Yansong Miao, and Alexander Ludwig. "ARHGAP12 suppresses F-actin assembly to control epithelial tight junction mechanics and paracellular leak pathway permeability." Cell Reports 44, no. 4 (2025): 115511. https://doi.org/10.1016/j.celrep.2025.115511
- Eleanor Martin, Rossana Girardello, Gunnar Dittmar, and Alexander Ludwig. "Time-resolved proximity proteomics uncovers a membrane tension-sensitive caveolin-1 interactome at the rear of migrating cells." eLife 13 (2024): e85601. https://doi.org/10.7554/eLife.85601
- Martin, E., Girardello, R., Dittmar, G., and Ludwig, A. "New insights into the organisation and regulation of the apical polarity network in mammalian epithelial cells." FEBS Journal (2021). https://doi.org/10.1111/febs.15710
- Tan, B., Yatim, S.M.J.M., Peng, S., Gunaratne, J., Hunziker, W., and Ludwig, A. "The mammalian Crumbs complex defines a distinct polarity domain apical of epithelial tight junctions." Current Biology (2020). https://doi.org/10.1016/j.cub.2020.05.032